What is the difference between peat based compost and peat free compost?

Peat adds acid. So, if you need to add acid to your soil, you want to use something with peat. We added peat to our blueberry plantings. If you don't need the acid, then get the peat-free stuff.

Peat based compost,as the name suggests, contains peat. Peat free compost does not contain peat but some other organic matter. This excercise is driven by the Green lobby who fear that the planet will run out of peat and implode.